#include <common/sha256.h>
#include <stdio.h> 
#include <string.h>
uint sha256_key[64] = {
  0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
  0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
  0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
  0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
  0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
  0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
  0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
  0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
};

void sha256_transform(SHA256_CTX *ctx, uchar data[]) {  
  uint a,b,c,d,e,f,g,h,i,j,t1,t2,m[64];

  for (i=0,j=0; i < 16; ++i, j += 4)
    m[i] = (data[j] << 24) | (data[j+1] << 16) | (data[j+2] << 8) | (data[j+3]);
  for ( ; i < 64; ++i)
    m[i] = SIG1(m[i-2]) + m[i-7] + SIG0(m[i-15]) + m[i-16];

  a = ctx->state[0];
  b = ctx->state[1];
  c = ctx->state[2];
  d = ctx->state[3];
  e = ctx->state[4];
  f = ctx->state[5];
  g = ctx->state[6];
  h = ctx->state[7];

  for (i = 0; i < 64; ++i) {
    t1 = h + EP1(e) + CH(e,f,g) + sha256_key[i] + m[i];
    t2 = EP0(a) + MAJ(a,b,c);
    h = g;
    g = f;
    f = e;
    e = d + t1;
    d = c;
    c = b;
    b = a;
    a = t1 + t2;
  }

  ctx->state[0] += a;
  ctx->state[1] += b;
  ctx->state[2] += c;
  ctx->state[3] += d;
  ctx->state[4] += e;
  ctx->state[5] += f;
  ctx->state[6] += g;
  ctx->state[7] += h;
}  

void sha256_init(SHA256_CTX *ctx) {  
  ctx->datalen = 0; 
  ctx->bitlen[0] = 0; 
  ctx->bitlen[1] = 0; 
  ctx->state[0] = 0x6a09e667;
  ctx->state[1] = 0xbb67ae85;
  ctx->state[2] = 0x3c6ef372;
  ctx->state[3] = 0xa54ff53a;
  ctx->state[4] = 0x510e527f;
  ctx->state[5] = 0x9b05688c;
  ctx->state[6] = 0x1f83d9ab;
  ctx->state[7] = 0x5be0cd19;
}

void sha256_update(SHA256_CTX *ctx, uchar data[], uint len) {  
  uint t,i;

  for (i=0; i < len; ++i) { 
    ctx->data[ctx->datalen] = data[i]; 
    ctx->datalen++; 
    if (ctx->datalen == 64) { 
      sha256_transform(ctx,ctx->data);
      DBL_INT_ADD(ctx->bitlen[0],ctx->bitlen[1],512); 
      ctx->datalen = 0; 
    }  
  }  
}  

void sha256_final(SHA256_CTX *ctx, uchar hash[]) {  
  uint i; 

  i = ctx->datalen; 

  // Pad whatever data is left in the buffer. 
  if (ctx->datalen < 56) { 
    ctx->data[i++] = 0x80; 
    while (i < 56) 
      ctx->data[i++] = 0x00; 
  }  
  else { 
    ctx->data[i++] = 0x80; 
    while (i < 64) 
      ctx->data[i++] = 0x00; 
    sha256_transform(ctx,ctx->data);
    memset(ctx->data,0,56); 
  }  

  // Append to the padding the total message's length in bits and transform. 
  DBL_INT_ADD(ctx->bitlen[0],ctx->bitlen[1],ctx->datalen * 8);
  ctx->data[63] = ctx->bitlen[0]; 
  ctx->data[62] = ctx->bitlen[0] >> 8; 
  ctx->data[61] = ctx->bitlen[0] >> 16; 
  ctx->data[60] = ctx->bitlen[0] >> 24; 
  ctx->data[59] = ctx->bitlen[1]; 
  ctx->data[58] = ctx->bitlen[1] >> 8; 
  ctx->data[57] = ctx->bitlen[1] >> 16;  
  ctx->data[56] = ctx->bitlen[1] >> 24; 
  sha256_transform(ctx,ctx->data);

  // Since this implementation uses little endian byte ordering and SHA uses big endian,
  // reverse all the bytes when copying the final state to the output hash. 
  for (i=0; i < 4; ++i) { 
    hash[i]    = (ctx->state[0] >> (24-i*8)) & 0x000000ff; 
    hash[i+4]  = (ctx->state[1] >> (24-i*8)) & 0x000000ff; 
    hash[i+8]  = (ctx->state[2] >> (24-i*8)) & 0x000000ff;
    hash[i+12] = (ctx->state[3] >> (24-i*8)) & 0x000000ff;
    hash[i+16] = (ctx->state[4] >> (24-i*8)) & 0x000000ff;
    hash[i+20] = (ctx->state[5] >> (24-i*8)) & 0x000000ff;
    hash[i+24] = (ctx->state[6] >> (24-i*8)) & 0x000000ff;
    hash[i+28] = (ctx->state[7] >> (24-i*8)) & 0x000000ff;
  }  
}  
